# 数组乘以整型可以复制数组append好多次
[0] * 10
# >>> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[0,1] * 10 
# >>> [0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1]